A joint forms where articulating surfaces have both concave and convex areas, permitting a wide range of movements.

the answer is admiramos

the rule for verbs is whoever you are referring to (in this case 'nosotros'), you need to change the ending of the word.

nosotros - amos

yo - o

tu - as

el, ella, usted - a

ellos, ellas, ustedes - an

(examples: nosotros bailamos (instead of bailar) or yo hablo (instead of habla)

friedrich meischer discovered it in white blood cell